Remove the (now obsolete) logic for clearing the first pixels of line zero.

.vscode/settings.json

@@ -12,5 +12,9 @@
     "editor.trimAutoWhitespace": true,
     "editor.useTabStops": false,
     "C_Cpp.intelliSenseEngine": "Default",
-    "files.insertFinalNewline": true
+    "files.insertFinalNewline": true,
+    "files.associations": {
+        "locale": "cpp",
+        "string": "cpp"
+    }
 }

src/emucore/tia/TIA.cxx

@@ -108,9 +108,6 @@ void TIA::setFrameManager(AbstractFrameManager *frameManager)
     },
     [this] () {
       onFrameComplete();
-    },
-    [this] () {
-      onRenderingStart();
     }
   );
 
@@ -1134,12 +1131,6 @@ void TIA::onFrameStart()
   }
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void TIA::onRenderingStart()
-{
-  myXAtRenderingStart = myHctr > 68 ? myHctr - 68 : 0;
-}
-
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void TIA::onFrameComplete()
 {

src/emucore/tia/TIA.hxx

@@ -461,12 +461,6 @@ class TIA : public Device
      */
     void onFrameStart();
 
-    /**
-     * This callback is invoked by FrameManager when the visible range of the
-     * current frame starts.
-     */
-    void onRenderingStart();
-
     /**
      * This callback is invoked by FrameManager when the current frame completes.
      */

src/emucore/tia/frame-manager/AbstractFrameManager.cxx

@@ -21,8 +21,7 @@
 AbstractFrameManager::AbstractFrameManager() :
   myLayout(FrameLayout::pal),
   myOnFrameStart(nullptr),
-  myOnFrameComplete(nullptr),
-  myOnRenderingStart(nullptr)
+  myOnFrameComplete(nullptr)
 {
   layout(FrameLayout::ntsc);
   reset();
@@ -55,18 +54,16 @@ void AbstractFrameManager::nextLine()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void AbstractFrameManager::setHandlers(
   callback frameStartCallback,
-  callback frameCompletionCallback,
-  callback renderingStartCallback
+  callback frameCompletionCallback
 ) {
   myOnFrameStart = frameStartCallback;
   myOnFrameComplete = frameCompletionCallback;
-  myOnRenderingStart = renderingStartCallback;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void AbstractFrameManager::clearHandlers()
 {
-  myOnFrameStart = myOnFrameComplete = myOnRenderingStart = nullptr;
+  myOnFrameStart = myOnFrameComplete = nullptr;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -109,12 +106,6 @@ void AbstractFrameManager::notifyFrameComplete()
     myCurrentFrameFinalLines;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void AbstractFrameManager::notifyRenderingStart()
-{
-  if (myOnRenderingStart) myOnRenderingStart();
-}
-
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void AbstractFrameManager::layout(FrameLayout layout)
 {

src/emucore/tia/frame-manager/AbstractFrameManager.hxx

@@ -40,8 +40,7 @@ class AbstractFrameManager : public Serializable
      */
     void setHandlers(
       callback frameStartCallback,
-      callback frameCompletionCallback,
-      callback renderingStartCallback
+      callback frameCompletionCallback
     );
 
     /**
@@ -250,14 +249,6 @@ class AbstractFrameManager : public Serializable
      */
     void notifyFrameComplete();
 
-    /**
-     * Signal rendering start. Mandatory only of actual rendering happens.
-     *
-     * TODO: This (and the related handling in the TIA) should be unnecessary
-     * after refactoring.
-     */
-    void notifyRenderingStart();
-
     /**
      * The internal setter to update the frame layout.
      */
@@ -317,7 +308,6 @@ class AbstractFrameManager : public Serializable
      */
     callback myOnFrameStart;
     callback myOnFrameComplete;
-    callback myOnRenderingStart;
 
   private:
 

src/emucore/tia/frame-manager/FrameManager.cxx

@@ -165,7 +165,6 @@ void FrameManager::setState(FrameManager::State state)
       break;
 
     case State::frame:
-      notifyRenderingStart();
       myVsyncLines = 0;
       myY = 0;
       break;